thomson



(No Model.)

B. THOMSON.

2 Sheets-Sheet? ELECTRIC LAMP.

Patented Aug. 14, 1883.

WL ivzests'e s N. PETERS. Photo'liihogmpher. Washinglon- D. C.

UNITE STATES PATENT OFFICE.

ELIHU THOMSON, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO THE THOM- SON-HOUSTON ELECTRIC COMPANY, OF BOSTON, MASS.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 283,168, dated August 14, 1883,

Application filed February 1, I883. (l\'o model.)

To all whom, it may concern.-

Be it known that I, ELIHU THOMSON, a citizen of the United States, auda resident of New Britain, in the county of Hartford and State of 5 Connecticut, have invented certain new and useful Improvements in Electric Lamps, of which the following is a specification.

My invention relates to the feeding and'adjusting mechanism for electric-arc lamps, and

I is intended more particularly as an improvement upon a form of lamp described in a prior application for patent filed by me the 2d day of January, 1883, No. 80,641. In that application I have described and claimed a com- 1 bination in which a main-circuit and derivedcircuit magnet are connected by independent devices with the same feed-regulating devices or clutch in such a way that the operation of feeding maybe effected by the action of the de- 2c rived-circuit magnet only, the core or armature of the main-circuit magnet acting as the lifting-power to separate the carbons, and remaining during the operations of feeding in the position which it first assumes when the 2 5 lamp starts into action.

In my prior application. referred to the de rived-circuit magnet may lower the clutch to release the carbon without interference with or from the connection of the main-circuit 3'0 magnet with the clutch, and it would be con sistent with the invention therein described, when an excess of lifting-power is given to the main-circuit magnet, that the derived-circuit magnet should begin to act contrariwise upon 3 5 the clutch before the main-circuit-magnet core or armature has completed its movement in the act of separating the carbons. In my present invention, however, the main and derived circuit magnets act solely and separately in 40 their respective ways, and the adjustment is such that no movement is imparted to the de rived-circuit-magnet core or armature until after the main-circuit core or armature has come to rest and'the arc has begun to lengthen by consumption, and the construction of the derived-circuit magnet is such that its core or armature has an extended range of motion and may rise any distance under the effects of the same current in its coils until said are is less in length and the current in the derived coils 5o diminishes. I find that to give the shunt or derived-circuit magnet in the combination a uniform attraction for the same current in all positions of its core or armature is a decided improvement, as in this case, just as soonas 5 5 a certain resistance of are is reached, the derived-circuit magnet will lift and raise its armature indefinitely, so as to Tower and feed the carbon, and the current inthe derived circuit does not require to increase more than a fraction of the amount necessary in the ordinary differential systems as used, because in such systems the lifting action is a decreasing one, made so by restraining-springs, or by the cores or armatures on being lifted reaching less effective positions, and consequently requiring a continuous increase in the derived circuit, ordinarily to be obtained only by a constant or continued increase in the length of are by consumption.

In the accompanying drawings, Figure l is a side elevation of one form of lamp embodying my invention. Fig. 2 is a side view of an electro-magnet for use in the derived circuit, constructed to give a uniform pull in the va 7 rious positions of its armature with the same strength of current, and shows the armature retracted. Fig. 3 is a view at right angles from the line of sight of Fig. 2. Fig. 4 shows the armatin-e in the other of its extreme posi- 8otions. Fig. 5 is atop view of the clutch mechanism which engages with the carbon-carrier. Fig. 6 is a side view of another form of lamp embodying my invention. Fig. 7 illustrates the application of my invention to the wellknown wheel-lamp.

In Fig. 1, R indicates the usual carbon-carrying rod, supporting the upper or positive carbon, E, opposite the lower or negative carbon, E, which latter is usually stationary. C 0 is the clutch which engages with said carrier for the purpose of lifting it to formthe are or releasing it to allow a slow feed, and which is here shown as vconsisting of a clamp-body, a, through which the carrier passes, a pivoted 5 toe or dog, 1), adapted to bear against the car rier, and an extension, 0, from saidtoe, provided with a spring, S which tends to hold the toe against the carrier, so as to prevent the latter from moving downward. A stop, 1, dis-, engages the clutch-toe when the clamp is lowered sufficiently to bring the extension 0 against the stop. Other forms of lifting and feeding clamp might be used in place of the one shown, which is a form describedin some of my prior applications and patents. The clutch O is supported by a lever, L", pivoted on a standard, P, which is fixed on the plate M, carrying the lamp-magnets, &c.

L indicates a rocking table or lever, having two fnlcrums at points a m, respectively, where it is pivoted or jointed to the armatu res or equivalent parts of the main and derived circuit electromagnets D S, and having an upwardly-extending arm, 1), which is con neeted by a link, L, with the SLIPPOItlHQ-IGXGI If. As will be readily seen, if the lever L be raised at n and rock on m, (thelatter pointbeing for the time iixed,) the upper end of 1) will swing to the left, and thus lift the clutch and rod It, while if, after being somoved, the point on be raised, (a being stationary the upper end of 1) will swing back to the right, so as to lower the clutch and cause a release of the carbon.

The main-circuit magnet may be of any desired form or construction, though it is here shown as of the same form as the derivedcircuit magnet. The latteris so constructed that its armature B shall, when the lifting-power of the core becomes sufficient to raise it, have a uniform pull through its whole range of movement from one stop to the other, and the magnet is so adjusted that the armature shall be lifted only alter the arc has attained the predetermined normal length and has begun to lengthen still further by consumption. In other words, the derived-circuit magnet does not begin to act to reverse the movement of the clutch until. after the main-circuit magnet has finished its work of lifting the carbon and forming the arc, and its action even then is accomplished without any movement on the part of the main-circuit magnet and without disturbance with or from the same. The derived-circuit magnet may be constructed to give the desired uniformity of pull in any well-known way, but is constructed most simply, in the manner shown in Figs. 1, 2, 3, and

GI, of a curved faced armature moving opposite and transversely to a rounded pole of the magnet-core, and is by preference hung from and in magnetic connection with the opposite pole. Fig. 2 shows the armature as retracted. Fig. l shows it attracted to its extreme position. In this position the attraction is the same (with the same strength of current) as in Fi 2, al though the armature is nearer the core, this being due to the extension of the pole end of the armature beyond the core, as shown, inwhich position the attraction-between the core and the extension that would tend to draw the armature in a reverse direction would of course be greater than when the polar mass extending beyond the core is smaller. The action in this particular might also be explained on the supposition that the true pole of the armature is carried by the movement of the armature into less effective position with relation. to the core. Uniformity is secured in. intermediate positions by the curved form of the armaturepole face, which is so curved that the counteracting effects due to increase in mass of that portion of the armature-pole beyond the core to the right shall correspond with the increased attractive effects due to increased proximity of the armature and core as the armature mo vcs up under the effects of the current in the derived-circuit coils. Other forms of magnet might be used for securing the desired uniformity of pull with changed positions of the armaturesuch, for instance, as those shown in Patents Nos. 253,958, 258,6Sl, and 265,993, granted tome, although I do not wish to be understood as limiting myself to any special form or device for securing the desired uniformity of pull after the derived-circuit current becomes sufficient to move the armature.

The main-circuit magnet I) is in the direct or main circuit, as indicated, and the circuit branches t 25 into two paths, one being the usual derived cireuitaroiuld the arc, and including the derived-circuit-magnet coils S, while the other passes to the are by means of a brush, \V, bearing on rod It, and rejoins the derived-circuit branch at Y. In the form of lamp shown the magnet-poles may act as stops for the armatures, or the edge of the magnet spool head may have the same function. In the former case the pole is faced with some non-magnetic material to prevent sticking. The main-circuit magnet may be of any de sired strength sufficient to keep its armature fully drawn up during the normal operation of. the lamp. The derived-circuit magnet is so adjusted, as before mentioned, that it will not act to raise its armature until the are in.- creases beyond a determinate normal length. \Vhenit does so act, the armatrn'e drawn up with a continuous uniform pull until the arc is again restored to its normal length.

The operation is briefly as follows: lVhen no current is passing, the parts are in theposition shown, the toe b disengaged from. R, the carbons are in-icontact, and the armatures are against theirback stops. \Vhen current passes,

main-circuit magnet lifts its armature, swinging p to the left and raising the upper carbon in obvious manner to form. an arc of a determinate length. The armature of derived circuit magnet S retains its position during this operation, the current flowing in the derived circuit being insufficient to lift it. 'W hen the arc increases in length, the derived-circnit magnet becomes sufficiently strong to lift its armature, and the upper end of p is swung to the right, so as to lower the clutch and release or partially release the carrier It, which then feeds until the arc is restored to its normal length. In this operation main-circuit magnet D takes no part, it being in the main or general circuit, where fluctuations of arc will not be felt perceptibly or practically, especially if an automatic regulator be used on the generator, and being also of sufficient strength. tohold its armature up. It is not essential that the armature of D should have a uniform pull in its changed positions, nor that mechanical devices ofthe particular form herein shown should be. used for imparting reverse movements to the same regulating-clutch or other mechanism under the separate action of the main and derived circuit magnets, respectively. Fig. 6 illustrates one of the many modifications in these respects that maybe employed. In this case the main-circuit magnet D has a movable core, A which is attached to a lever, G, and lifts the derived-circuit magnet S, sup ported on the lever G. The armature B of magnet S supports the clutch O, and is held by a retractiiigqveight, Z, against its stop 2; when G is lifted. The clutch O is thus raised and the arc is formed without any'movement of B toward the core 'of S. The core A remains raised, and when the current increases in S, owing to consumption at the are, the armature B is drawn down so as to lower the clutch and allow the feed to take place. Fig. 7 illustrates the application of the invention to a gear-train lamp. j

A further obvious application of my invention is to the well-known form of gear-train lamp in which the retarded gear-train connected with the carrier is mounted in a lever that is moved in one direction or the other by the magnet system, so as to lift the carbon or to carry the train out of engagement with its detent, so that it may revolve and allow the carbon to feed. In Fig. 7, I have merely indicated a portion of the parts of such lamp, the usual and wellknown train of gears between the carrier and the vibrating fl'y or escapement or other part with which the detent acts being omitted for the sake of simplicity. I11 this figure the le ver that supports the parts is indicated at T and as pivoted at 15. The pinion gearing with the carrier R is indicated at 16, and at 17 is indicated the ordinary escapement-wheel and fly, which latter is prevented from vibrating-by coming into engagement with a pivoted stop or detent, 18, thus holding the train from movement and keeping the carbon at rest. The lever L operated in the same manner as in Fig. 1, is connected by a link with the lever T, and when actuated by the m-aincircuit magnet raises the lever T and causes the separation of the carbons in the well-known way. The reverse movement lowers the lever and allows the carbon to descend when the fly is removed from engagement with the detent.

It is obvious that my invention may be applied to other forms of lamps by simply eonnecting the lever If with, that portion of the regulating mechanism which serves, when moved in one direction, to cause a separation of the carbons, and when moved in the opposite direction to cause a feed of said carbons.

I make no broad claim herein to the combi nation, with the feed-regulating clutch, clamp, or other device, of main and derived circuit magnets, both connected with such device and adjusted and operating in such a way that the main-circuit magnet shall cause a separation of the carbons, and shall thereafter retain its position, so as to have no function. in producing the feed, while the derived acts upon the same devices to cause the feed, without interferenee with or from the main-circuit magnet, as this combination, in its broad terms, forms the subject of the prior application filed by me, and hereinbefore referred to; nor do I make thereupon reversely and independently of the other to move the same in opposite directions, said main-circuit magnet being adj usted to hold its armature or equivalent part in lifted position during normal operation of the lamp, while the derived-circuit magnet is adjusted to act only on an increase of the are beyond normal length, and has with the same strength a constant or uniform pull on the feed mcehanism in all positions of its armature.

2. The combination, in an electric lamp, of a lifting and feeding clutch or clamp, alifting main-circuit eleetro-magnet whose core or ar mature retains its attracted position during feeding operation, a core or armature controlled by a derived-cireuit coil and responding only on an increase inthe length of are beyond the normal point, said core or armature having a uniform pull in its changed positions, and independent actuating and supporting connections between the main and derived circuit armatures and the common clam p or clutch, so that they may act independently of one another, in the manner described, the one to lift and the other to lower the clamp.

3. The combination, with a common carbon separating and adjusting mechanism for an electric lamp, of a main-circuit electro-magnet for separating the carbons connected with. said common mechanism, so as to actuate or support the same, and adjusted to retain its position during normal operation, and a derivedcircuit magnet acting reversely upon the same portion of said adjusting and feeding mechanism, to cause a feed independently of the maincircuit magnet, said derived-circuit magnet being adjusted to operate said mechanism only on an increase in the length of are beyond the normal, and being provided with an armature whose pole, moving before the magnet, is

curved or tapered, as and for the purpose set forth.

i. The combination, withalifting and feed clutch, ,of a pivoted table or lever, L, having the two fulcrnnis or points of support m 11, a main-circuit eleetro-inagnet connected at one of said points, and a derived;cirenit electroniagnet connected to the other point and exerting a pull uniform in the various positions of its armature, as and for the purpose set forth. 5. The combination of the clutch, the lever L", the table or lever L, i'ulcrnined or support ed at opposite points m a, and main and derived circuit magnets lifting the opposite ends of the lever dissiinnlta-neonsly, as and for the purpose set forth.

(i. The combination of the clutch, the lever L", table or lever L, having two inleruinsnpports at moi, 1nain-eireuit magnet whose armature is connected to one side of said table and of January, A. l). 1883.

ELTHU THOMSON.

Vitnesses: I

XV. O. \VAKEFIE'LI), E. \VI'LBUR RICE. 

